The ideas in this specification are generally applicable to hoses of different types including industrial hoses, for example, hoses used in spraying applications as well as watering hoses including domestic, say, garden hoses. One example of the hoses to which the ideas relate are garden water supplying hoses of the type which have an expanded and increased length state when pressurised due to water flowing therethrough and a contracted state in the absence of such pressure.
Typically such hoses have an outer fabric based layer which can contract and in effect crumple as the hose contracts in a non-water filled state and some form of internal elastic member for causing the hose to move to a contracted state in the absence of water pressure.
One such existing expandable hose is described in GB2490276A. That hose has an outer tube formed of a non-elastic and flexible material and an inner tube constructed of an elastic material. The outer tube and the inner tube have a first end attached together by a first coupler and a second end attached by a second coupler. The hose has a shorter length a non-water flow contracted state and a longer length in an expanded state where water pressure is applied to the interior of the elastic tube. The water flow path is through the inner elastic tube whereas the outer tube serves to control and contain expansion of the inner tube in the expanded state. In the contracted state the outer tube is in a crumpled or undulating state, whereas in the expanded state the outer tube is relatively taut and restrains the inner tube against further expansion.
A potential drawback with a hose of the construction described in GB2490276A is that there can be a tendency for hose failure due to one or other of the couplers failing to successfully hold the inner or outer tube after a period of use or more generally that there is a tendency for such hoses to fail after an extended period of use.
Thus it would be desirable to provide an improved design of hose with better reliability/durability.